From: Theodore Ts'o <tytso@mit.edu>
To: Hugh Dickins <hughd@google.com>
Cc: Zheng Liu <wenqing.lz@taobao.com>,
Yongqiang Yang <xiaoqiangnk@gmail.com>,
Allison Henderson <achender@linux.vnet.ibm.com>,
Lukas Czerner <lczerner@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH next/mmotm] ext4: fix cache_es after merge_left
Date: Thu, 27 Sep 2012 16:39:20 -0400 [thread overview]
Message-ID: <20120927203920.GB9585@thunk.org> (raw)
In-Reply-To: <alpine.LSU.2.00.1209271324060.2184@eggly.anvils>
On Thu, Sep 27, 2012 at 01:31:28PM -0700, Hugh Dickins wrote:
> Kernel build with CONFIG_DEBUG_SLAB or CONFIG_SLUB_DEBUG slub_debug=FPZ
> gives me kernel BUG at fs/ext4/extents_status.c:142! That's the
> BUG_ON(es->start + es->len < es->start) in extent_status_end() called
> from ext4_es_insert_extent(). tree->cache_es has been freed and poisoned.
>
> This comes from when ext4_es_try_to_merge_left() merges es into leftward
> es1, but ext4_es_insert_extent()'s out then updates cache_es to the freed
> extent_status. ext4_es_try_to_merge_right() does not pose a problem.
>
> Change ext4_es_try_to_merge_left() to return whichever extent_status
> should be recorded in tree->cache_es. Remove cache_es update from
> both of them, leaving that to ext4_es_insert_extent()'s out label.
>
> Signed-off-by: Hugh Dickins <hughd@google.com>
Hugh, thanks for finding this bug!
Zheng, you were going to send me an updated patch series; can you take
care of merging this patch into your patch series (and crediting Hugh
with a Signed-off-by as appropriate)?
Thanks!!
- Ted
next prev parent reply other threads:[~2012-09-27 20:39 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-27 20:31 [PATCH next/mmotm] ext4: fix cache_es after merge_left Hugh Dickins
2012-09-27 20:39 ` Theodore Ts'o [this message]
2012-09-27 22:53 ` Zheng Liu
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